Which of the following elements is responsible for maintaining turgor in cells?

Potassium helps in maintaining the turgidity of cells. For example,Increased concentration of ${{\mathrm{K}}^{+}}^{ }$, Cl– and malate ions in the vacuole of guard cells results in the production of osmotically active salts namely potasium chloride and potasium malate. This decrease  water potential resulting in endosmosis. Increased turgor of guard cells makes the outer wall of the guard cells to become more convex. The inner thick wall guard cell move apart. As a result stoma opens.